Esters of 1,2-diphenyl-cyclohex-1-ene-4-carboxylic acid

ABSTRACT

Esters of 1,2-diphenyl-cyclohex-1-ene-4-carboxylic-acid are effective plant growth regulating agents. They are useful for controlling wild oats in cereal cultures and for growth inhibition in different cultures, e.g. for the inhibition of suckers in tobacco plants.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation-in-part of our application, Ser. No. 713,477,filed Aug. 11, 1976, now abandoned.

The invention relates to esters of1,2-diphenyl-cyclohex-1-ene-4-carboxylic-acid with plant growthregulating activity, to compositions containing them and methods forinhibiting growth of plants e.g. tobacco suckers or controlling wildoats in cereal cultures with them.

The 1,2-diphenyl-cyclohex-1-ene-4-carbo xylic-acid esters compound toformula I ##STR1## wherein R is C₁ -C₁₈ alkyl, optionally substituted byhalogen, a C₁ -C₄ alkoxy or C₃ -C₈ cycloaliphatic rest or by phenyl orphenoxy, which in turn are optionally substituted by chlorine, bromine,C₁ -C₄ alkyl or C₁ -C₄ alkoxy. C₃ -C₁₈ alkenyl optionally substituted bychlorine, bromine or C₁ -C₄ alkoxy, C₃ -C₆ alkinyl, C₃ -C₁₂ cycloalkyloptionally substituted by chlorine, bromine or methyl; phenyl or benzyloptionally substituted by chlorine, bromine, C₁ -C₄ alkyl, C₁ -C₄alkoxy, nitro or trifluoromethyl,

U and V are hydrogen, chlorine or bromine, C₁ -C₄ alkyl, C₁ -C₄ alkoxy,nitro, or trifluoromethyl.

The 1,2-diphenyl-cyclohex-1-ene-4-carboxylic acid, which may also betermed 3,4-diphenyl-Δ3-tetrahydrobenzoic acid is known from Liebigs Ann.570 201 (1950). No mention is made in the literature of aplant-influencing activity. Such activity becomes particularly evidentin the present esters of this acid or in similar acids which aresubstituted in the phenyl ring according to this invention.

The following esters of 1,2-diphenyl-cyclohex-1-ene-4-carboxylic-acidwere noticably active. The ones wherein U and V are hydrogen. Furtherthose wherein R is C₁ to C₇ alkyl or C₃ to C₇ alkenyl optionallysubstituted by C₁ -C₄ alkoxy. Exceptional activity showed the esters of1,2-diphenyl-cyclohex-1-ene-4-carboxylic-acid wherein R is2-bromoethyl,2-fluoroethyl,2,2,2-trichloroethyl, isopropyl, isobutyl,neopentyl and especially the methyl ester.

The compounds of formula I are prepared by reacting acrylonitrile,acrylic acid or a derivative thereof according to formula II

    CH.sub.2 ═CH--COX                                      (II)

wherein X is halogen, hydroxyl or OR, with either a diene of formula III##STR2## in a Diels-Alder reaction, or with a compound of the formulaIIIa ##STR3## in a modified Diels-Alder reaction (Proc. Chem. Soc. 1963,217), which is followed, if acrylic acid is used, if desired by anesterification with the appropriate alcohol R--OH or a reactivederivative thereof or if acrylonitrile is used, initially by asaponification of the nitrile group to give the carboxyl group followedby optional esterification thereof. The substituents U and V are asdefined for formula I.

The process of the invention is consequently a cyclisation reaction inthe presence of a functional acid group, which in turn is either in theform of an acid or ester group, or, if desired, can be converted intosuch a group after the cyclisation is complete.

It will be readily understood that there are a number of ways ofaccomplishing this ester formation which is necessary before or aftercyclisation. The following possibilities are cited as examples:

(a) reaction of --COOH with the halide, preferably chloride or bromide,R-halogen in the absence, but preferably in the presence, of a base;

(b) reaction of --COOH with the alcohol R-OH in the presence of acidcatalysts (HCl, H₂ SO₄, Lewis acids);

(c) transesterification of --COOR' (OR' is any alcoholic or phenolicgroup) with an excess of the desired alcohol R-OH, preferably also inthe presence of an acid catalyst;

(d) reaction of a reactive acid derivative --COX with the alcohol R-OHor an alkali salt thereof, wherein X represents a halide or anotherreadily removable radical, such as benzene sulphate, tosylate, mesylateor the like.

Acid halides are customarily obtained by halogenating the carboxyl groupwith, for example, SO₂ Cl₂, COCl₂, (COCl)₂, PCl₅, PBr₅, SF₄ and thelike.

The conversion of a 1,2-diphenyl-cyclohexene-4-carboxylic acid intosalts is carried out in conventional manner with a corresponding basedefined in forformula I.

The cyclisation process of this invention is carried out at normalpressure or elevated pressure in the temperature range between 80° and200° C., preferably between 120° and 150° C., in solvents which aresuitable for Diels-Alder reactions, such as hydrocarbons (benzene,toluene, xylenes) [cf. H. Wollweber "Diels-Alder-Reaktionen", GeorgThieme Verlag, Stuttgart, 1972]. The process, however, can also becarried out in the absence of a solvent.

When using compound IIIa, the addition of dehydrating agents (splittingoff of 2 moles of water) is necessary to form compound III asintermediate. It is possible to use conventional agents, such as Al₂ O₃,p-toluenesulphonic acid, KHSO₄, acetic anhydride/sodium acetate etc.,for the dehydration.

The starting products of the formulae III and IIIa are partly knowncompounds are they can be obtained by methods which are known per se,for example:

"Grignard" reaction of the corresponding benzile derivatives ##STR4##[Bull. Soc. chim France 43, 873 (1928)]

Dimerisation of the corresponding acetophenone derivative (a)electrochemically, (b) by irradiation (h·v), (c) in the presence ofaluminium powder ##STR5## (a) [J. Am. Chem. Soc. 75, 5127 (1953)] (b)[Tetrahedron 25, 4501 (1969)]

(c) [J. Org. Chem. 37, 2367 (1972)]

To prepare the optionally unsymetrical compounds of the formula III orIIIa in which the U's and V's have different meaning it is necessary tocarry out a grignard reaction in one or two steps between diacetyl, CH₃--CO--CO--CH₃ and the different phenyl-magnesium-halogenides ##STR6##see J. Org. Chem. 28, 2154 (1963).

The following Examples illustrate the process of the present inventionincluding the manufacture of the starting products. The parts are partsby weight. Further compounds of the formula I which were obtained by thedescribed process are listed in the subsequent table.

EXAMPLE 1 (a) Manufacture of a starting product (1^(st) method)

A mixture of 50 parts of 2,3-diphenyl-2,3-dihydroxybutane and 0.5 partof freshly dehydrated KHSO₄ is distilled for 50 minutes at 11 Torr and200° C. bath temperature. The fraction which is collected within theboiling range of 150°-180° C./11 Torr yields 43.8 parts of crude2,3-diphenyl-1,3-butadiene. The product is stirred direct with 21.5parts of acrylic acid and 2 parts of hydroquinone under a nitrogenatmosphere for 3 hours at 130° to 140° C.

The cooled reaction product is treated with diethyl ether and extractedwith 1 normal NaOH. The aqueous phase is acidified with concentratedhydrochloric acid and extracted with diethyl ether. The organic phase isdried over Na₂ SO₄ and concentrated in vacuo to yield 21 parts of3,4-diphenyl-Δ³ -tetrahydrobenzoic acid with a melting point of136°-140° C.

(b) (2nd method)

A mixture of 7.2 parts of 2,3-diphenyl-2,3-dihydroxybutane, 3.2 parts ofacrylic acid, 0.1 part of p-toluenesulphonic acid and 0.3 part ofhydroquinone is dissolved in 12 parts of acetone and the solution iskept for 25 minutes in a Carious tube. The solution is concentrated invacuo and the oily residue is worked up as described in (a) above toyield 2.2 parts of 3,4-diphenyl-Δ³ -tetrahydrobenzoic acid with amelting point of 136°-140° C.

EXAMPLE 2

A mixture of 57 parts of 3,4-diphenyl-Δ³ -tetrahydrobenzoic acid and 5parts of concentrated H₂ SO₄ is kept for 18 hours in 500 parts by volumeof methyl alcohol at reflux temperature.

The solution is concentrated in vacuo and the oily residue is coveredwith a layer of ether and neutralised with 2 normal NaOH. The separatedorganic phase is dried over Na₂ SO₄ and concentrated in vacuo to yield57 parts of 3,4-diphenyl-Δ³ -tetrahydrobenzoic acid methyl ester.

Boiling point: 121°-125° C./0.001 Torr.

EXAMPLE 3

A mixture of 7.2 parts of 2,3-diphenyl-2,3-dihydroxy-butane, 3.8 partsof acrylic acid methyl ester, 0.1 part of p-toluenesulphonic acid and0.3 part of hydroquinone dissolved in 12 parts of acetic anhydride iskept in a Carius tube for 24 hours at 130°-140° C. The reaction productis distilled to yield 2.3 parts of 3,4-diphenyl-Δ³ -tetrahydrobenzoicacid methyl ester.

Boiling point: 121°-125° C./0.001 Torr.

EXAMPLE 4 (a) Manufacture of a starting product

27.8 parts of 3,4-diphenyl-Δ³ -tetrahydrobenzoic acid are suspended in amixture of 60 parts by volume of abs. chloroform and 0.8 part ofdimethyl formamide. Then 15.5 parts of thionyl chloride are addeddropwise at 0° C. in the course of 5 minutes. The mixture is stirred at0° C. for 15 minutes at room temperature and stirred for 20 minutes at40° C. The clear, yellow solution is concentrated in vacuo and dried ina high vacuum at 50° C. to yield 29 g of 3,4-diphenyl-Δ³-tetrahydrobenzoyl chloride.

Boiling point: 160° C./0.005 Torr.

(b) A solution of 14.25 g (0.048 mole) of 3,4-diphenyl-Δ³-tetrahydrobenzoyl chloride in 80 ml of abs. ether is added dropwise atroom temperature to a solution of 2.4 g (0.04 mole) of 1-propanol, 80 mlof abs. ether and 5 ml of pyridine. After 5 hours the reaction mixtureis filtered through silica gel. The end product,3,4-diphenyl-cyclohex-3-ene-1-carboxylic acid-n-propyl ester is elutedwith petroleum ether/ether (2:1) and distilled in vacuo. Yield: 7.2 g;b.p. (0.01 Torr) 150° C. (in a bulb tube). n_(D) ²⁵ =1.5665. Thefollowing compounds of the formula I are obtained in this manner or byone of the other methods indicated hereinabove:

    ______________________________________                                         ##STR7##                                                                     Com-                                                                          pound R                    Physical constant                                  ______________________________________                                        1     CH.sub.3             b.p. 121°-125° C.                                               /0.001 Torr                                        2     C.sub.2 H.sub.5      n.sub.D.sup.20 1.5802                              3     n-C.sub.3 H.sub.7    n.sub.D.sup.25 1.5665                              4     isoC.sub.3 H.sub.7   b.p. 165°-170° C.                                               /0.01 Torr                                         5     n-C.sub.4 H.sub.9    n.sub.D.sup.25 1.5617                              6     sec. C.sub.4 H.sub.9 n.sub.D.sup.25 1.5560                              7     tert.C.sub.4 H.sub.9 n.sub.D.sup.25 1.5430                              8     3-C.sub.5 H.sub.11   n.sub.D.sup.20 1.5560                              9     n-C.sub.8 H.sub.17   n.sub.D.sup.20 1.5270                              10    n-C.sub.12 H.sub.25  n.sub.D.sup.20 1.5179                              11    n-C.sub.18 H.sub.37  m.p. 45°-47° C.                      12    2-bromoethyl         n.sub.D.sup.20 1.5708                              13    6-chlorohexyl(n)     n.sub.D.sup.20 1.5625                              14    3-nitrobutane-2-yl   n.sub.D.sup.25 1.5585                              15    2,2,2-trichloroethyl n.sub.D.sup.20 1.5800                              16    2-cyanoethyl         m.p. 77°-80° C.                      17    2-methoxyethyl       n.sub.D.sup.20 1.5691                              18    2-n-butoxyethyl      n.sub.D.sup.20 1.5575                              19    3-ethoxypropyl       n.sub.D.sup.20 1.5600                              20    2[2-butoxyethoxy]ethyl                                                                             n.sub.D.sup.25 1.5485                              21    2-allyloxyethyl      n.sub.D.sup.20 1.5652                              22    2-n-octylthioethyl   n.sub.D.sup.20 1.5523                              23    3-acetylpropyl       n.sub.D.sup.25 1.5636                              24                                                                                   ##STR8##            n.sub.D.sup.20 1.5640                              25    2-fluoroethyl        m.p. 65°-66° C.                      26    2-chloroethyl        m.p. 69°-70° C.                      27    2-iodoethyl          n.sub.D.sup.25 1.6072                              28    3-chloropropyl(n)    n.sub.D.sup.25 1.5753                              29    3-bromopropyl(n)     n.sub.D.sup.25 1.5845                              30    n-C.sub.5 H.sub.11   n.sub.D.sup.25 1.5557                              31    isoC.sub.4 H.sub.9   n.sub.D.sup.25 1.5592                              32    l-ethoxycarbonyl-ethyl                                                                             n.sub.D.sup.20 1.5570                              33    3-N,N-dimethylamino- n.sub.D.sup.20 1.5675                                    propyl                                                                  34                                                                                   ##STR9##            m.p. 210°-212° C.                    35    cyclohexylmethyl     n.sub.D.sup.20 1.5590                              36    cyclooctylmethyl     n.sub.D.sup.25 1.5582                              37    cyclohexene-(3)-1-yl-                                                                              n.sub.D.sup.25 1.5697                                    methyl                                                                  38    3-phenylpropyl       n.sub.D.sup.20 1.5873                              39    2[4-methoxyphenyl]ethyl                                                                            m.p. 65°-67° C.                      40    2-phenoxyethyl       n.sub.D.sup.20 1.5850                              41                                                                                   ##STR10##           n.sub.D.sup.25 1.5610                              42                                                                                   ##STR11##           n.sub.D.sup.20 1.5730                              43                                                                                   ##STR12##           oil                                                44                                                                                   ##STR13##           n.sub.D.sup.20 1.5892                              45                                                                                   ##STR14##           n.sub.D.sup.20 1.5671                              46    2-propenyl           n.sub.D.sup.20 1.5762                              47    4-pentenyl           n.sub.D.sup.20 1.5652                              48    3,7-dimethyl-octa-   n.sub.D.sup.20 1.5594                                    2,6-dien-1-yl                                                           49    1-chloroprop-2-yl    n.sub.D.sup.25 1.5671                              50    1-bromoprop-2-yl     n.sub.D.sup.25 1.5822                              51    1,4-dibromobut-2-yl  oil                                                52    2,3-dibromopropyl(n) n.sub.D.sup.25 1.5865                              53    9-octadecenyl        n.sub.D.sup.20 1.5290                              54    2-propinyl           n.sub.D.sup.20 1.5806                              55    3-hexinyl            n.sub.D.sup.20 1.5682                              56    3-chloro-buten-(2)-1-yl                                                                            n.sub.D.sup.25 1.5741                              57    3-phenyl-propen-(2)-1-yl                                                                           n.sub.D.sup.20 1.6065                              58    cyclopropyl          oil                                                59    cyclohexyl           n.sub.D.sup.20 1.5639                              60    cyclooctyl           n.sub.D.sup.25 1.5632                              61    cyclododecanyl       m.p. 95°-100° C.                     62    benzyl               n.sub.D.sup.20 1.5935                              63    4-chlorobenzyl       n.sub.D.sup.20 1.5962                              64    4-methoxybenzyl      n.sub.D.sup.20 1.5910                              65    4-methylbenzyl       n.sub.D.sup.20 1.5930                              66    phenyl               n.sub.D.sup.20 1.5881                              67    3-bromophenyl        n.sub.D.sup.20 1.6105                              68    3,4-dichlorophenyl   n.sub.D.sup.20 1.5982                              69    4-chloro-2-methylphenyl                                                                            m.p. 118° C.                                70    4-methylthiophenyl   oil                                                71    4-t-butylphenyl      n.sub.D.sup.20 1.5782                              72    3-nitrophenyl        n.sub.D.sup.25 1.5940                              73    4-sulphophenyl       oil                                                74    3-cyanophenyl        n.sub.D.sup.25 1.5910                              75    3-trifluoromethylphenyl                                                                            n.sub.D.sup.25 1.5598                              76    3-N,N-dimethylamino- n.sub.D.sup.25 1.6000                                    phenyl                                                                  77    N-methylpiperidin-4-yl                                                                             oil                                                78    tetrahydrofuran-3-yl m.p. 102-105° C.                            79    3-methoxycarbonyl-2- b.p. 210-215° C.                                                       /0.001 Torr                                              methyl-prop-2-en-1-yl                                                   80    2-N,N-dimethylamino- b.p. 165° C.                                                           /0.001 Torr                                              ethyl                                                                   81    2-nitroethyl         oil                                                82    cyclopropylmethyl    oil                                                83    1-cyclopropyl-eth-1-yl                                                                             n.sub.D.sup.25 1.5643                              ______________________________________                                    

The following compounds of the formula I are also obtained in the mannerof one of the methods indicated above:

    ______________________________________                                         ##STR15##                                                                    Com-                              Physical                                    pound U          V        R       constant                                    ______________________________________                                        84    4-Cl       H        CH.sub.3                                                                              n.sub.D.sup.20 1.5881                       85    4-Cl       H        C.sub.2 H.sub.5                                     86    3-CH.sub.3 H        CH.sub.3                                                                              n.sub.D.sup.20 1.5684                       87    3-CH.sub.3 H        C.sub.2 H.sub.5                                     88    4-CH.sub.3 H        CH.sub.3                                                                              n.sub.D.sup.20 1.5763                       89    4-CH.sub.3 H        allyl                                               90    3-COOH     H        CH.sub.3                                            91    4-phenyl   H        CH.sub.3                                                                              m.p.. 163°-168°               92    2-Cl       4-Cl     isoC.sub.3 H.sub.7                                  93    4-Br       H        CH.sub.3                                                                              n.sub.D.sup.20 1.6180                       94    4-C.sub.2 H.sub.5                                                                        H        CH.sub.3                                            95    2-Cl       3-Cl     C.sub.2 H.sub.5                                     96    3-Br       H        CH.sub.3                                                                              n.sub.D.sup.20 1.6085                       97    3-CF.sub.3 H        CH.sub.3                                            98    4-SO.sub.3 H                                                                             H        C.sub.2 H.sub.5                                     99    4-CN       H        CH.sub.3                                                                              oil                                         100   4-N(CH.sub.3).sub.2                                                                      H        CH.sub.3                                            101   3-NO.sub.2 H        CH.sub.3                                            102   3-CH.sub.3 O                                                                             H        CH.sub.3                                            103   3-CH.sub.3 O                                                                             5-CH.sub.3 O                                                                           CH.sub.3                                                                              oil                                         ______________________________________                                    

The active substances of the present invention of the formula I, and thecorresponding compositions which contain them, intervene in thephysiological processes of plant development and can be used for variouspurposes in connection with the increase in yield, ease of harvestingand labour-saving in measures taken on cultivated plants. The variouseffects of these active substances depend substantially on the time ofapplication (from the ripening stage of the plant) and on theconcentrations employed. However, these effects are in turn differentdepending on the species of plant.

Compound structures of 4-phenyl-cyclohex-(3 or 4)-ene-1-carboxylates aredisclosed within a substantial group of compounds in general form inGerman Offenlegungsschrift No. 1,900,658. Anti-fertility properties areascribed to such compounds, which appear to make them suitable forrodent control. No particulars are given on effects on plants. Thatcompounds of the formula I of the present invention act on plants istherefore completely surprising.

The active substances of this invention of the formula I, and thecompositions which contain them, influence the plant growth. Thesupporting tissues of the stems of treated plants are strengthened. Theformation of undesired suckers in various plant species is diminished,for instance the vegetative growth of vines is inhibited. Further thevegetative growth of soya bean and other leguminous plants is reducedand the generative growth promoted, whereby a direct increase in theyield is achieved.

Special mention is also to be made of the possibility of inhibiting thegrowth of suckers in tobacco plants with the active substances of thepresent invention, when the leading shoot has been cut off shortlybefore flowering in order to bring about the desired increase in growthof the leaves.

The principal kind of plant regulation, however, resides in the specialproperty of the compounds of the formula I to effect in specific weeds agrowth inhibition so pronounced that it approximates to a herbicidalaction and the compounds can be used in practice for this purpose. Whenapplied to a large number of monocotyledonous and dicotyledonous weeds(Setaria, Alopecurus, Sinapis, Galium etc.), the compounds effect astunted growth. From the point of view of maintaining cultivated land,this effect provides a particularly advantageous weed control to theextent that, independently of the growth of useful plants, a uniform,low plant cover is retained, which counteracts soil erosion by wind orwater. The marked selective activity of the compounds of the formula I,which either has no effect on the important major crops, such as sugarbeet, wheat, barley, rye and others, or even--as in types ofcereals--increases the breaking strength of the plant through slightgrowth reduction, results in an economically very interesting method ofprotecting cultivations of plants from the spread of weeds. Aparticularly advantageous feature of the compounds of the formula I isthe pronounced herbicidal-like growth inhibition of wild oats (Avenafatua), which are among the most important grass-like weeds in crops ofuseful plants, above all in cereals. Experience has shown wild oats tobe among the most difficult weeds to control. They are controlled onlyimperfectly by a few herbicides, but not at all by the majority ofcommercially available herbicides.

The invention therefore provides simultaneously a method of controllingweeds in crops of useful plants by applying compounds of the formula I,which cause stunted growth or compositions which contain them.

Such a method of inhibiting plant growth does not bring about any changein the sense of a mutation in the life cycle of the plant which isdetermined by genetic characteristics.

The maintenance of pure grass cultivations, such as those in publicparks and gardens, in urban areas, industrial sites, or along mainroads, railway embankments or the embankments of water bodies, has to beconsidered in connection with the reduction in growth of grasses. In allsuch cases it is normally necessary to cut the turf or grassperiodically. This operation is not only time-consuming, complicated andexpensive in respect of labour and machinery, but involves the personnelconcerned and road users in considerable hazard in the traffic sector.

For this reason there is therefore an urgent need in areas withextensive traffic networks on the one hand to maintain and care for thegrassy covering necessary for strengthening road shoulders andembankments on traffic routes, and on the other hand to keep it atreasonable height by simple means during the entire vegetation period.This need is fulfilled in a very advantageous manner by applying thecompounds of the formula I.

The active substances of the formula I can be applied to the surface tobe treated simultaneously or successively with further activesubstances. These active substances can be both fertilisers, traceelement agents or other preparations which influence plant growth.However, they can also be selective herbicides, insecticides,fungicides, bactericides, nematicides, molluscicides or mixtures ofthese preparations, if appropriate together with additional carriers orfurther additives which assist application.

Suitable carriers or additives may be solid or liquid and correspond tothe substances conventionally used in the art of formulation, forexample: natural and regenerated substances, solvents, dispersingagents, wetting agents, stickers, thickeners, binders or fertilizers.

For application, the compounds of formula I can be in the followingapplication forms.

Solid preparations: dusts, tracking agents, granulates (coatedgranulates, impregnated granulates and homogranulates);

Liquid preparations:

(a) water-dispersible active substance concentrates: wettable powders,pastes or emulsions;

(b) solutions.

To these mixtures can also be added additives which stabilise the activesubstance and/or non-ionic, anionic and cationic substances, which forexample improve the adhesion of the active ingredients on plants orparts of plants (stickers) and/or ensure a better wettability (wettingagents) and dispersibility (dispersing agents). Examples of suitablestickers are: olein/chalk mixture, cellulose derivatives (methylcellulose, carboxymethyl cellulose), hydroxyethyl glycol ethers ofmonoalkyl and dialkyl phenols having 5 to 15 ethylene oxide radicals permolecule and 8 to 9 carbon atoms in the alkyl radical, lignin sulphonicacids, their alkali metal and alkaline earth metal salts, polyethyleneglycols ethers (carbowaxes), fatty alcohol polyethylene glycol etherhaving 5 to 20 ethylene oxide radicals per molecule and 8 to 18 carbonatoms in the fatty alcohol moiety, condensation product of urea andformaldehyde, and also latex products.

Water-dispersible concentrates of the active substance, i.e. wettablepowders, pastes and emulsifiable concentrates, are compositions whichcan be diluted with water to any desired concentration. They consist ofactive substance, carrier, optionally additives which stabilise theactive substance, surface-active substances and anti-foam agents and,optionally, solvents.

The content of active substance in the above described compositions isbetween 0.1 and 95%, preferably between 1 and 80%. Application forms canbe diluted to as low a content of active substance as 0.001%. As a rulethe rates of application are from 0.1 to 10 kg of active substance perhectare, preferably from 0.25 to 5 kg per hectare.

The active substances of formula I can be formulated for example in thefollowing way:

Dusts

The following substances are used for the preparation of (a) a 5% (b) a2% dust:

(a)

5 parts of active substance

95 parts of talcum

(b)

2 parts of active substance

1 part of highly dispersed silicic acid

97 parts of talcum

The active ingredients are mixted and ground with the carriers.

Granulate

The following substances are used to obtain a 5% granulate:

5 parts of active substance

0.25 parts of epichlorohydrin

0.25 parts of cetyl polyglycol other

3.50 parts of polyethylene glycol

91 parts of kaolin (particle size 0.3-0.8 mm)

The active substance is mixed with epichlorohydrin and dissolved in 6parts of acetone, then the polyethylene glycol and cetyl polyglycolether are added. The resultant solution is sprayed onto kaolin and theacetone is subsequently evaporated in vacuo.

Wettable Powder

The following ingredients are used to prepare a 25% wettable powder.

25 parts of active substance,

4.5 parts of calcium lignin sulphonate,

1.9 parts of Champagne chalk/hydroxyethyl cellulose mixture (1:1),

1.5 parts of sodium dibutyl naphthalenesulphonate,

19.5 parts of silicic acid,

19.5 parts of Champagne chalk,

28.1 parts of kaolin;

The active substances are intimately mixed in suitable mixers with theadditives, and the mixture is then milled in appropriate mills androllers. Wettable powders are obtained which can be diluted with waterto give suspensions of any desired concentration.

Emulsifiable Concentrates

The following substances are used to produce a 25% emulsifiableconcentrate:

250 parts of active substance

150 parts of a condensation product of 1 mole of tributylphenol and 10moles of ethylene oxide as wetting agent. The preparation is bulked to avolume of 1000 ml with xylene.

By diluting such concentrates with water it is possible to obtainemulsions of any desired concentration which are suitable forapplication to plants to inhibit their growth. To illustrate the plantgrowth influencing properties of the compounds of the formula I, theherbicidal/growth-inhibiting activity was determined by means of thefollowing tests.

TEST A Herbicidal post-emergence application in the greenhouse

Plant seeds were sown into pots filled with sterilized earth, so that 8to 20 plants could develop. Then they were left to emerge and when theyoung plants had 2 to 3 true leaves after 10 to 12 days, they weresprayed with a testing solution containing the active substance. Theconcentration was so chosen as to correspond to an application rate in afield of 8, 4, 2, 1 and 1/2 kg of active substance per hectare. Theplants were then left to develop in the green-house for three weeksunder optimal conditions of light, temperature and humidity and regularwatering. Then the test was evaluated and the state of the plantsassessed according to the following scale

9 plant develops normally, like untreated control plants

8-5 light to medium stages of damage

5-2 severe stages of damage

1 plant died

-- plant at corresponding concentration not tested.

The results are summarized in the table below.

    __________________________________________________________________________    compound No. 1    15   2    25   26                                           application                                                                   rate kg/ha   8 4 2 1                                                                            8 4 2 1                                                                            4 2 1 1/2                                                                          8 4 2 1                                                                            8 4 2 1                                      __________________________________________________________________________    plant                                                                         barley       7 8 9 9                                                                            5 6 7 9                                                                            4 6 7 8                                                                            7 8 9 9                                                                            9 9 9 9                                      wheat        8 9 9 9                                                                            9 9 9 9                                                                            4 6 7 8                                                                            7 9 9 9                                                                            9 9 9 9                                      maize        2 4 6 7                                                                            6 7 9 9                                                                            5 8 9 9                                                                            4 8 9 9                                                                            6 7 9 9                                      sorgho       9 9 9 9                                                                            7 8 9 9                                                                            3 7 8 9                                                                            9 9 9 9                                                                            8 9 9 9                                      rice         9 9 9 9                                                                            8 9 9 9                                                                            9 9 9 9                                                                            8 9 9 9                                                                            9 9 9 9                                      soya         3 3 4 4                                                                            4 4 4 6                                                                            3 3 3 4                                                                            4 5 6 6                                                                            4 4 4 6                                      cotton       7 7 7 7                                                                            6 6 7 7                                                                            8 8 8 9                                                                            5 5 6 6                                                                            3 4 4 4                                      avena fatua  4 4 4 4                                                                            4 4 5 6                                                                            3 3 3 4                                                                            3 3 4 4                                                                            4 4 4 4                                      lolium perenne                                                                             8 9 9 9                                                                            9 9 9 9                                                                            6 6 7 9                                                                            9 9 9 9                                                                            8 9 9 9                                      alopecurus myosuroides                                                                     6 7 8 9                                                                            5 7 7 7                                                                            3 4 4 6                                                                            5 6 7 8                                                                            6 7 8 9                                      cyperus esculentus                                                                         7 - - 7                                                                            9 - 9 -                                                                            7 - 9 -                                                                            8 - 9 -                                                                            5 - 7 -                                      rottboellia exaltata                                                                       7 9 9 9                                                                            7 9 9 9                                                                            8 9 9 9                                                                            7 9 9 9                                                                            7 8 8 9                                      digitaria sanguinalis                                                                      7 8 9 9                                                                            8 9 9 9                                                                            6 6 8 9                                                                            7 9 9 9                                                                            6 9 9 9                                      setaria italica                                                                            8 9 9 9                                                                            7 8 9 9                                                                            7 7 8 9                                                                            9 9 9 9                                                                            7 9 9 9                                      echinochloa crus galli                                                                     8 9 9 9                                                                            8 9 9 9                                                                            6 7 8 9                                                                            8 9 9 9                                                                            8 9 9 9                                      beta vulgaris                                                                              7 8 9 9                                                                            8 9 9 9                                                                            9 9 9 9                                                                            9 9 9 9                                                                            9 9 9 9                                      sesbania exaltata                                                                          7 7 9 9                                                                            7 8 9 9                                                                            8 9 9 9                                                                            5 8 8 8                                                                            7 7 8 9                                      amaranthus retroflexus                                                                     6 7 9 9                                                                            6 7 7 7                                                                            7 7 9 9                                                                            5 6 8 8                                                                            5 7 7 9                                      sinapis alba 3 4 4 4                                                                            6 6 6 6                                                                            3 4 6 6                                                                            4 6 6 6                                                                            3 4 4 5                                      ipomoea purpurea                                                                           4 4 4 4                                                                            4 5 7 7                                                                            4 5 7 8                                                                            5 7 7 9                                                                            3 6 7 8                                      galium aparine                                                                             6 6 6 6                                                                            5 6 7 7                                                                            5 6 6 7                                                                            7 7 7 7                                                                            7 7 7 7                                      pastinaca sativa                                                                           7 9 9 9                                                                            9 9 9 9                                                                            9 9 9 9                                                                            8 9 9 9                                                                            7 9 9 9                                      matricaria chamomille                                                                      7 8 9 9                                                                            8 9 9 9                                                                            8 8 9 9                                                                            8 9 9 9                                                                            9 9 9 9                                      sida spinosa 6 6 7 9                                                                            7 7 9 9                                                                            7 7 8 8                                                                            3 6 9 9                                                                            4 6 6 6                                      rumex sp.    5 5 6 6                                                                            4 6 6 9                                                                            3 3 3 4                                                                            5 6 6 6                                                                            4 4 5 5                                      __________________________________________________________________________    compound No. 29   3     31  46   5    8    83                                 application                                                                   rate kg/ha   8 4 2 1                                                                            8 4 2 1                                                                            8 4 2 1                                                                            8 4 2 1                                                                            8 4 2 1                                                                            8 4 2 1                                                                            8 4 2 1                            __________________________________________________________________________    plant                                                                         barley       9 9 9 9                                                                            7 8 8 9                                                                            9 9 9 9                                                                            7 7 9 9                                                                            7 8 9 9                                                                            9 9 9 9 9                                                                          9 9 9 9                            wheat        9 9 9 9                                                                            7 9 9 9                                                                            7 9 9 9                                                                            8 9 9 9                                                                            9 9 9 9                                                                            9 9 9 9                                                                            9 9 9 9                            maize        6 7 9 9                                                                            6 7 9 9                                                                            5 7 9 9                                                                            6 7 7 9                                                                            6 7 8 8                                                                            7 7 9 9                                                                            7 8 9 9                            sorgho       9 9 9 9                                                                            7 9 9 9                                                                            9 9 9 9                                                                            7 8 9 9                                                                            9 9 9 9                                                                            9 9 9 9                                                                            9 9 9 -rice 9 9 9 9 8 9 9 9 9                                                 9 9 9 7 7 9 9 9 9 9 9 9 9 9                                                   9 9 9 9 9                          soya         5 5 7 8                                                                            4 5 6 6                                                                            4 4 4 4                                                                            4 4 4 5                                                                            5 6 6 6                                                                            4 4 7 7                                                                            7 7 7 8                            cotton       3 3 4 5                                                                            4 5 5 5                                                                            4 4 4 7                                                                            6 7 7 8                                                                            4 4 6 6                                                                            6 7 7 7                                                                            4 6 6 7                            avena fatua  3 3 3 6                                                                            3 3 4 5                                                                            3 3 3 6                                                                            3 3 4 5                                                                            3 4 4 5                                                                            3 3 4 4                                                                            4 4 4 4                            lolium perenne                                                                             9 9 9 9                                                                            7 8 9 9                                                                            8 9 9 9                                                                            9 9 9 9                                                                            7 9 9 9                                                                            8 9 9 9                                                                            9 9 9 9                            alopecurus myosuroides                                                                     6 6 7 8                                                                            4 6 6 8                                                                            4 6 6 7                                                                            3 3 5 6                                                                            4 5 5 9                                                                            8 9 9 9                                                                            4 6 6 8                            cyperus esculentus                                                                         8 - 8 -                                                                            7- 9 9                                                                             7 - 8 -                                                                            - - - -                                                                            8 - 8 -                                                                            9 - 9 -                                                                            8 - 9 -                            rottboellia exaltata                                                                       9 9 9 9                                                                            8 8 9 9                                                                            8 8 9 9                                                                            6 8 8 9                                                                            8 9 9 9                                                                            7 8 8 9                                                                            8 9 9 9                            digitaria sanguinalis                                                                      4 8 8 9                                                                            5 7 9 9                                                                            6 6 7 7                                                                            9 9 9 9                                                                            9 9 9 9                                                                            8 9 9 9                                                                            7 7 9 9                            setaria italica                                                                            4 7 7 9                                                                            5 7 4 4                                                                            6 7 7 8                                                                            8 9 9 9                                                                            8 8 9 9                                                                            7 8 9 9                                                                            4 4 7 7                            echinochloa crus galli                                                                     9 9 9 9                                                                            6 7 9 9                                                                            9 9 9 9                                                                            7 8 9 9                                                                            9 9 9 9                                                                            9 9 9 9                                                                            9 9 9 9                            beta vulgaris                                                                              9 9 9 9                                                                            6 9 9 9                                                                            9 9 9 9                                                                            8 8 9 9                                                                            9 9 9 9                                                                            8 9 9 9                                                                            9 9 9 9                            sesbania exaltata                                                                          7 8 9 9                                                                            4 7 9 9                                                                            7 8 9 9                                                                            7 8 9 9                                                                            6 7 8 9                                                                            9 9 9 9                                                                            7 8 9 9                            amaranthus retroflexus                                                                     7 7 8 9                                                                            7 8 9 9                                                                            7 7 8 9                                                                            6 6 7 7                                                                            6 6 7 8                                                                            6 7 8 9                                                                            8 8 9 9                            sinapis alba 5 5 7 9                                                                            3 4 8 9                                                                            3 3 3 4                                                                            3 3 4 6                                                                            4 4 4 4                                                                            4 5 5 5                                                                            5 5 5 6                            ipomoea purpurea                                                                           4 7 7 7                                                                            4 5 6 7                                                                            4 6 7 7                                                                            4 4 6 6                                                                            4 7 8 8                                                                            6 6 7 7                                                                            6 7 8 9                            galium aparine                                                                             7 7 9 9                                                                            6 6 6 6                                                                            8 8 8 8                                                                            5 6 6 6                                                                            7 7 7 7                                                                            5 5 5 5                                                                            8 8 9 9                            pastinaca sativa                                                                           9 9 9 9                                                                            6 8 9 9                                                                            9 9 9 9                                                                            8 9 9 9                                                                            9 9 9 9                                                                            9 9 9 9                                                                            9 9 9 9                            matricaria chamomille                                                                      9 9 9 9                                                                            6 7 9 9                                                                            7 9 9 9                                                                            9 9 9 9                                                                            9 9 9 9                                                                            9 9 9 9                                                                            9 9 9 9                            sida spinosa 4 4 6 6                                                                            4 4 9 9                                                                            6 6 6 9                                                                            7 7 8 8                                                                            4 4 7 4                                                                            7 8 9 9                                                                            6 9 9 9                            sp.          4 6 6 6                                                                            3 4 9 9                                                                            4 5 5 5                                                                            3 4 5 5                                                                            4 4 4 4                                                                            4 4 5 5                                                                            6 6 6 6                            __________________________________________________________________________

These compounds do not show excellent herbicidal activity in this test.Monocotyledonous plants are hardly damaged with the exception of avenafatua. The activity is better towards some of the dicotyledonous plants.The possibility of controlling avena fatua (wild oats) in cultures ofcereal, barley wheat, sorgho or rice, is given. In order to investigatethis, a field test was undertaken.

SMALL-FIELD TEST

A field in northern Switzerland was divided into several small lots.These lots were then seeded with the following cultures.

wheat of the variety "Probus"

hard wheat

barley of the variety "Nymphe"

oats of the variety "Flamingskrone"

In between the culture plants the were seeded rows with the weeds bromustectorum, alopecurus myosuroides, lolium perenne and avena fatua.

Four weeks, after the seeds have emerged and the young plants show 3 to6 true leaves, the lots were sprayed with emulsions of the substance tobe tested in concentrations of 4, 2, 1 and 1/2 kg/ha. Some of the lotswere left untreated to serve as control. The test was evaluated aftersix weeks and the state of the plants assessed according to the abovegiven scale. The results are summarized in the table below.

    ______________________________________                                        compound                                                                      application      No. 1       Destun ®                                     rate kg/ha       4 2 1 1/2   4 2 1 1/2                                        ______________________________________                                         plant                                                                        wheat "Probus"   6 6 9 9     2 8 9 9                                          hard wheat       5 6 9 9     6 7 7 9                                          barley "Nymphe"  5 7 9 9     7 8 9 9                                          oats "Flamingskrone"                                                                           2 2 2 3     2 8 9 9                                          bromus tectorum  9 9 9 9     2 3 8 9                                          alopecurus myosuroides                                                                         9 9 9 9     9 9 9 9                                          lolium perenne   9 9 9 9     4 5 8 9                                          avena fatua      1 2 2 3     8 9 9 9                                          ______________________________________                                    

The compound "Destun®"[1,1,1-trifluoro-N-(4-phenylsulfonyl-o-tolyl)-methane-sulfamide] was notchosen for comparison because of structural likeness but because weexpected it to show a similar activity.

FURTHER FIELD TESTS

Further tests were then conducted in different countries where becauseof climatic and topographic conditions, avena fatua has become theproblem weed in cereal. Because of its morphological likeness with theculture, this weed is difficult to control. The fields chosen for tests,were divided after emergence of the wheat (culture into big lots of 100m². These lots were then treated with emulsions of active substanceuntil amounts of 4, 2, 1 and 1/2 kg/ha were applied. The part of thefield that was not treated served as control. The test was evaluated (asabove) after six weeks. The results are summarized in the table below.

    ______________________________________                                        compound                                                                      application      1           Destun ®                                     rate in kg/ha    4 2 1 1/2   4 2 1 1/2                                        ______________________________________                                        country: Switzerland                                                          wheat            8 8 9 9     2 8 9 9                                          avena fatua      1 2 2 3     8 9 9 9                                          country: France                                                               wheat            6 7 8 9     8 8 9 9                                          avena fatua      2 4 4 6     3 8 9 9                                          country: Morocco                                                              wheat            7 8 8 9     7 8 9 9                                          avena fatua      3 3 5 8     2 2 9 9                                          country: Italy                                                                wheat            7 8 9 9     8 8 9 9                                          avena fatua      4 4 8 8     9 9 9 9                                          country: USA                                                                  wheat            8 8 8 9     8 8 9 9                                          avena fatua      2 2 2 2     3 8 9 9                                          ______________________________________                                    

TEST B Growth Inhibition of Grasses (Post Emergence Method)

Seeds of the grasses lolium perenne, Poa pratensis, Festuca ovina andDactylis glomerata were sown in plastic dishes filled with anearth/turf/sand mixture and watered normally. Each week the emergentgrasses were cut back to a height of 4 cm above the soil and thensprayed with aqueous spray broths of the active substances of theformula I 40 days after sowing and 1 day after the last cutting. Theamount of active substance corresponded to a rate of application of 5 kgper hectare. The growth of the grasses was evaluated 10 and 21 daysafter application using the following linear scale rating:

1=pronounced inhibition (no further growth from the time of application)

9=no inhibition (growth as untreated control)

The results are given in the table below.

    ______________________________________                                        Compound No.  1      2      3    6    26    42                                application                                                                   rate in kg/ha 5      5      5    5     5     5                                ______________________________________                                        Lolium perenne                                                                              7      8      8    5    6     8                                 Poa pratensis 5      5      6    3    3     7                                 Festuca       4      4      5    3    3     6                                 Dactylis glomerata                                                                          3      6      4    2    3     5                                 ______________________________________                                    

Growth Inhibition in Cereals

In the same manner as with grasses, the growth inhibition of differentcrop-cereals was tested in the green-house. The test was run exactly inthe same manner as with the grasses. The results are given in the tablebelow.

    __________________________________________________________________________    Compound No.                                                                           1   3   6   26  41  42  44  54                                       application                                                                   rate in kg/ha                                                                          6 2 6 2 6 2 2 6 6 2 6 2 6 2 6 2                                      __________________________________________________________________________    wheat    5 6 6 7 4 5 5 8 6 8 4 6 4 5 7 8                                      rye      --                                                                              --                                                                              --                                                                              --                                                                              4 5 --                                                                              --                                                                              --                                                                              --                                                                              6 7 6 7 --                                                                              --                                     barley   6 7 3 7 5 6 3 8 5 7 6 7 5 7 5 7                                      rice     6 0 --                                                                              --                                                                              8 9 --                                                                              --                                                                              5 6 7 7 9 9 7 9                                      __________________________________________________________________________

TEST C Growth Inhibition in Soya Beans

Soja plants of the variety "Hark" were grown from earthenware pots in agreen house under controlled, optimal conditions for their growth. Threeweek after they had emerged, the young plants were sprayed until dripoffwith a test-liquor, containing one of the compounds to be tested in theindicated concentrations of respectively 100 and 500 ppm. Some of theplants were left untreated to serve as control.

The test was assessed four weeks after this treatment. The height of theplant was measured and evaluated according to the following scale:

1 strong inhibition, no further growth after application. Medium heightof plant about 18 cm.

2-8 intermediate stages of inhibition.

9 no inhibition, plant growth like untreated control plant. Mediumheight about 40 cm.

The results are summarized in the table below.

    ______________________________________                                        Compound No.    growth inhibition                                             application conc.                                                                             500 ppm      100 ppm                                          ______________________________________                                        1               2            3                                                2               4            6                                                3               2            6                                                6               2            4                                                14              1            8                                                26              3            9                                                41              2            4                                                42              1            9                                                44              3            9                                                45              3            7                                                54              3            9                                                ______________________________________                                    

TEST D Inhibition of the Growth of Side Shoots (Suckers) inTobacco-Plants

In the green-house tobacco plants of the variety "Nicotina" were grown.10 weeks after seeding, shortly before flowering, the main shoot (stem)was cut off. The day after, groups of three plants were sprayed fromabove with 10 ml of an aqueous emulsion of the test-compound. Theconcentrations chosen corresponded to 12, 6, 3 and 1.5 kg per hectare.Two weeks after this treatment, the inhibitory action on the topmost sixshoots was evaluated. The length of the sucker-shoot i.e. the shoots,that had grown after cutting off the main shoot was measured andcompared to those of groups of untreated control plants. As comparison"Off-Shoot T®", a commercially used product for this purpose was used.

The results were evaluated as follows:

9 normal sucker growth (100%) as in untreated control plants

8-2 percentually reduced growth of suckers 1 no growth after treatment(no suckers developed)

The results are given in the table below

    ______________________________________                                                      application                                                     Compound tested                                                                             rate in kg/ha   result                                          ______________________________________                                        1             6               2                                                             3               2                                                             1.5             2                                               2             6               2                                                             3               2                                                             1.5             3                                               4             6               2                                                             3               2                                                             1.5             3                                               42            6               2                                                             3               2                                                             1.5             2                                               47            6               2                                                             3               2                                                             1.5             3                                               63            6               2                                                             3               2                                                             1.5             2                                               76            6               2                                                             3               2                                                             1.5             2                                               mixture C.sub.9                                                                             12              4                                               and C.sub.10  6               7                                               alkanols      3               9                                               ______________________________________                                    

We claim:
 1. A method for controlling Avena fatua (wild oats) incultures of cereal which comprises applying to cereal fields infestedwith the weed Avena fatua in post-emergence application a herbicidallyeffective amount of an ester of 1,2-diphenyl-cyclohex-1-ene-4-carboxylicacid of the formula ##STR16## wherein R is C₁ -C₇ alkyl, optionallysubstituted by halogen, C₁ -C₄ alkoxy, C₃ -C₈ cycloalkyl, by phenyl orphenoxy unsubstituted or substituted by chlorine, bromine, C₁ -C₄ alkylor C₁ -C₄ alkoxy;C₃ -C₇ alkenyl, optionally substituted by chlorine,bromine or C₁ -C₄ alkyl; C₃ -C₆ cycloalkyl optionally substituted bychlorine, bromine or methyl; phenyl or benzyl unsubstituted orsubstituted by chlorine, bromine, C₁ -C₄ alkyl, C₁ -C₄ alkoxy, nitro ortirfluoromethyl; and U and V are hydrogen, chlorine, bromine, C₁ -C₄alkyl, C₁ -C₄ alkoxy, nitro or trifluoromethyl.
 2. The method accordingto claim 1, wherein U and V are hydrogen.
 3. The method according toclaim 1, wherein R is C₁ -C₇ alkyl or C₃ -C₇ alkenyl optionallysubstituted by C₁ -C₄ alkoxy.
 4. The method according to claim 1,wherein R is selected from among, methyl 2-bromoethyl,2,2,2-trichloroethyl, 2-fluoroethyl, isopropyl, and isobutyl.
 5. Themethod according to claim 1, wherein said ester is the methyl ester of1,2-diphenyl-cyclohex-1-ene-4-carboxylic-acid.
 6. The method of claim 1,wherein R is ethyl.
 7. The method of claim 1, wherein R is n-propyl. 8.The method of claim 1, wherein R is n-butyl.
 9. The method of claim 1,wherein R is cyclopropyl-1'-ethyl.